Pattern welding is the practice in sword and knife making of forming a blade of several metal pieces of differing composition that are forge-welded together and twisted and manipulated to form a pattern. Often mistakenly called Damascus steel, blades forged in this manner often display bands of slightly different patterning along their entire length. These bands can be highlighted for cosmetic purposes by proper polishing or acid etching. Pattern welding was an outgrowth of laminated or piled steel, a similar technique used to combine steels of different carbon contents, providing a desired mix of hardness and toughness. Although modern steelmaking processes negate the need to blend different steels, pattern welded steel is still used by custom knifemakers for the cosmetic effects it produces.
A contemporary pattern-welded sword blade made by Danish swordsmith Ejvind Nørgård. The blade shows a chevron pattern with opposing twists and straight laminate alternating.
An image of a modern pattern welded knife blade, showing the dramatic patterning on the side below, and the layering of the steel in the spine above. Acid etching darkens the 1080 plain carbon steel more than it does the 15N20 low alloy nickel steel, producing alternating bands of light and dark on the surface.
A knife is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least 2.5 million years ago, as evidenced by the Oldowan tools. Originally made of wood, bone, and stone, over the centuries, in step with improvements in both metallurgy and manufacturing, knife blades have been made from copper, bronze, iron, steel, ceramic, and titanium. Most modern knives have either fixed or folding blades; blade patterns and styles vary by maker and country of origin.
A Bowie knife of pattern-welded steel
Characteristic parts of a knife
Morakniv carbon steel knife
Knife blade mass production